(SportsNetwork.com) - Now is not the time for the Boston Celtics to begin playing poorly with a postseason spot on the line.

The Celtics look to get back on track Sunday versus the Detroit Pistons and have lost two in a row after winning five straight and seven of eight games.

Boston is eighth in the Eastern Conference standings - two games behind Miami and just a half-game ahead of both Indiana and Charlotte. Brooklyn sits a game off the pace of the Celtics, who dropped a 101-89 decision at San Antonio Friday night.

Evan Turner scored 17 points, Avery Bradley had 16 and Jae Crowder posted 14 off the bench for the Celtics, who shot 39.8 percent and were down by a 32-19 score after the first quarter.

Celtics rookie Marcus Smart helped get Boston within 56-42 at halftime by netting eight second-quarter points, the last two on a driving basket with 15.2 seconds remaining. However, the Celtics lost further ground in the third quarter as San Antonio turned the game into a rout.

A 13-2 sequence, during which Spurs forward Kawhi Leonard recorded the first 11 points, extended the Spurs' lead to 82-58 with two minutes remaining in the third, and the hosts were ahead by as many as 25 early in the fourth.

The Celtics' frustration showed in the final frame, which was marred by Smart's ejection with 8:56 left after he struck Spurs forward Matt Bonner in the groin with a punch.

"It's an unacceptable play," Celtics coach Brad Stevens said of Smart's punch. "You can't do that. Simple as that."

The NBA agreed with Stevens and suspended Smart one game. He will not be on the floor versus the Pistons and is eligible to return against Brooklyn Monday.

Detroit has won two of three games following a 10-game slide and hopes to put the brakes on an eight-game road losing streak.

The Pistons handed the Chicago Bulls a 107-91 defeat Saturday at The Palace of Auburn Hills and were led by Reggie Jackson's 22 points and 11 assists. Caron Butler scored 20 points, Kentavious Caldwell-Pope added 15 and Andre Drummond chipped in 14 points with nine rebounds.

"I'm just happy with the way the team performed," Jackson said. "Did a great job to battle and pull through."

Chicago had a 36-14 scoring advantage in the second quarter, but the Pistons made it count with a 27-12 difference in the final stanza.

The Pistons turned the ball over just four times and shot 48.9 percent.

Detroit is 5 1/2 games behind Boston for the East's final playoff spot and lost to the Celtics, 109-102, in overtime on Dec. 3 at TD Garden. The two teams will meet again April 8 at The Palace.

Detroit took three of four meetings with Boston last season and has won seven of the past 10 games in this series.